Good info Talyn, thanksWhat foam is best for guns?
The best foam for gun cases is polyethylene (abbreviated PE) because polyethylene is closed cell, which prevents moisture from absorbing into it. No matter how wet PE foam gets the liquid stays at the surface so it can be wiped clean.
Open cell polyurethane will absorb moisture, oils, & cleaning solvents causing it to break down much quicker than PE, and will get extremely gross over time.
https://www.caseclub.com/what-foam-is-best-for-guns/